9 research outputs found

    Estudio de comunidades de matorral mediterráneo II

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    Conjunto de guiones de prácticas de Ecología, correspondientes al bloque temático sobre el estudio de comunidades, centrado en el análisis de la diversidad de las comunidades presentes en el territorio objeto de estudio, y su respuesta a la perturbación. Acompañan dos archivos Excel de ejemplo, y el simulador de distribuciones de datos de vegetación

    European rabbit (Oryctolagus cuniculus) engineering effects promote plant heterogeneity in Mediterranean dehesa pastures

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    Mammalian herbivores can have dramatic etfects on the vegetation through different mechanisms, and may therefore modify resource distribution or create habitat for other species. Organisms that cause such changes are classified as ecosystem engineers. The European rabbit ( Orycto/agus cunicu/us) is a semifossorial mammal native to the lberian Peninsula and a keystone species in Mediterranean foodwebs. Rabbits are central-place foragers, but few studies have analysed their ecosystem engineering effects in the vicinity ofwarrens. Here, we explored the role of rabbits as ecosystem engineers in Mediterranean pastures in central Spain. We studied the spatial patterns and internal heterogeneity in the vegetation community of different spatial subunits created by rabbits (warrens, the warren influence area, and latrines). Within the different subunits, rabbit activities gave rise to patches and gradients with different plant species richness, diversity and height. and a high internal heterogeneity (dissimilarity) in floristic composition. Through different mechanisms, they have a significant effect on species coexistence and competitive interactions, and increase the number of available ni ches for plants which otherwise would not be able to establish. In conclusion, rabbits can act as allogenic ecosystem engineers in Mediterranean pastures, increasing heterogeneity and contributing to the high biodiversity of Mediterranean annual pastures

    Externalidades Ambientales del cultivo del olivar en España

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    Este trabajo se enmarca dentro del proyecto Extersial II (continuación del proyecto Externalidades Ambientales en Sistemas Agroalimentarios Locales), que tiene como objetivo el estudio de las externalidades ambientales del cultivo de olivar en España, desarrollando indicadores que permitan cuantificar cada una de ellas. Una de las externalidades negativas estudiadas en el proyecto es la erosión laminar del terreno (de manera potencial), para la cual la herramienta más común de análisis a nivel mundial es la ecuación RUSLE (Renard et al., 1997). Este método desarrolla diferentes parámetros, todos ellos relacionados con el ámbito espacial, ya que su cálculo se realiza a partir de características inherentes a cada posición en el terreno (altura, pendiente, orientación, etc.). Esto convierte a los SIG en una herramienta indispensable para el trabajo. Sin embargo, existe una gran variedad de métodos propuestos para el cálculo de dichos parámetros; por lo que, antes de implementar esta ecuación en ArcMap, es necesario realizar un estudio comparativo de dichas metodologías y de sus resultados. Nuestro punto de partida ha sido el MDE (Modelo Digital de Elevaciones) de 5m de paso de malla disponible en el centro de descargas del CNIG-IGN. El proceso de cálculo ha requerido la realización de múltiples operaciones algebraicas con capas ráster, la creación de varias capas intermedias o diversas comparaciones y combinaciones entre ellas; además de necesitar otro tipo de elementos, como por ejemplo, el modelo hidrológico. El resultado del trabajo es una metodología consistente para el cálculo de la erosión laminar potencial a través de ArcMap; con la que se ha podido calcular por completo el modelo de erosión laminar potencial de la región de Sierra Mágina (Jaén).N

    Simplifying data acquisition in plant canopies- Measurements of leaf angles with a cell phone

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    1.Canopies are complex multilayered structures comprising individual plant crowns exposing a multifaceted surface area to sunlight. Foliage arrangement and properties are the main mediators of canopy functions. Theleaves act as light traps whose exposure to sunlight varies with time of the day, date and latitude in a trade-off between photosynthetic light harvesting and excessive or photoinhibitory light avoidance. To date, ecological research based upon leaf sampling has been limited by the available technology, with which data acquisition becomes labour intensive and time-consuming, given the overwhelming number of leaves involved. 2. In the present study, our goal involved developing a tool capable of measuring a sufficient number of leaves to enable analysis of leaf populations, tree crowns and canopies. We specifically tested whether a cell phone working as a 3D pointer could yield reliable, repeatable and valid leaf angle measurements with a simple gesture. We eval-uated the accuracy of this method under controlled conditions, using a 3D digitizer, and we compared perfor-mance in the field with the methods commonly used. We presented an equation to estimate the potential proportion of the leaf exposed to direct sunlight (SAL) at any given time and compared the results with those obtained by means of a graphical method. 3.We found a strong and highly significant correlation between the graphical methods and the equation presented. The calibration process showed a strong correlation between the results derived from the two methods with a mean relative difference below 10%. The mean relative difference in calculation of instantaneous exposure was below 5%. Our device performed equally well in diverse locations, in which we characterized over 700 leaves in a single day. 4.The new method, involving the use of a cell phone, is much more effective than the traditional methods or digitizers when the goal is to scale up from leaf position to performance of leaf populations, tree crowns or canopies. Our methodology constitutes an affordable and valuable tool within which to frame a wide range of ecological hypotheses and to support canopy modelling approaches

    GUARDIANES: Aprendiendo a aplicar la Ecología para un mundo sostenible

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    Depto. de Biodiversidad, Ecología y EvoluciónDepto. de Investigación y Psicología en EducaciónDepto. de Filología ClásicaFac. de Ciencias BiológicasFac. de EducaciónFac. de FilologíaFALSEsubmitte
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